Currently, automotive interior back lighting requires a bezel or other plastic piece and a light source. The bezel is attached to a trim panel such as an instrument panel, console, or door panel. The light source is typically used to backlight a switch or knob. The bezel mounts in an opening in the trim panel and a portion of the bezel rests on top of the trim panel. The portion that rests on top of the trim panel can visually detract from the clean styling of the trim panel.
In certain automotive interior applications, back lighting is used to convey messages to the vehicle occupants or allow the occupants to locate knobs and/or switches at night. Backlighting of an object requires a multitude of parts to be assembled in order to direct the light from the source to the proper location. U.S. Pat. No. 5,842,769 entitled “Automotive Apparatus and Method Using Bulb Socket Retention of Components” relates generally to an apparatus and method for retaining lamp components with a bulb socket and specifically to an automotive back-lit switch using a bulb socket to retain a lamp reflector. Many of these components are custom designed for the particular application. These assemblies are expensive to fabricate, stock, and assemble.
Several U.S. patents disclose the use of a laser to generate extremely small holes in an automotive instrument panel around an air bag opening. U.S. Pat. No. 5,632,914 entitled “Motor Vehicle Air Bag Cover having a Skin with a Virtually Invisible Tear Seam Formed by Miniature Holes ”. The '914 patent discloses forming a tear seam, above an air bag door in the thin elastic plastic skin of a vehicle instrument panel. The tear seam being formed with a plurality of extremely small (less than 0.0005″) laser machined holes. These holes are not observable to a person of normal vision when viewed from the passenger compartment. U.S. Pat. No. 5,744,776 entitled “Apparatus and for Laser Preweakening an Automotive Trim Cover for an Air Bag Deployment Opening”. The '776 patent discloses a process for preweakening the inside of an automotive trim piece cover layer of various constructions by use of a laser beam so as to enable formation of an air bag deployment opening in the trim piece formed at the time the air bag deploys. Although these references teach forming openings in an vehicle instrument panel with a laser, they fail to teach locating a light source behind the openings and using the formed openings as illumination light pipes.